The Superhero Database Classification number, or SHDB Class, is a number that represents the overall 'power' of a character. All traits of a character are used for calculating the Classification.
What it DOESN'T mean
This doesn't mean that a higher class would always beat a lower class character. But the bigger the difference in Class is, the more obvious it is who'll win in a fight.
How is this calculated
( INT^1.3 + (STR*0.5 )^2 + (SPE*0.5)^2 + DUR^1.6 + (POW + (SPS*SPL))^2 + COM^1.8 ) ^ TIER
Super Power Score and Level
Every Super Power has a score (SPS) that is used to calculate the Class. Each Super Power also has 3 levels (SPL). The level is set when connecting that Super Power to a character. The level determines the final score, of the Super Power, being used in the calculation.
Yeah, no, Selene won't even be affected by her psionics she is far too strong for Alice.
Alice has faced scary opponents but Selene, while not scary would make any opponent Alice has faced look like a child, Alice got tossed around by an enhanced Jill Valentine and Selene would do the same, she would toss Alice the most Alice could do would be to use her telekinesis to buy herself some time, but at the end of the day Selene is too much for her.